British Prime Minister Theresa May has full confidence in finance minister Philip Hammond, her spokesman said on Thursday, following criticism from former Chancellor Nigel Lawson.

The Chancellor said: "I will be in the USA this week to demonstrate that Global Britain is not just a phrase, it is a reality".

Mr Hammond leaves behind him a party still struggling to agree over the UK's approach to Brexit, with comments made by the Chancellor about how the country is preparing to for a "no deal" scenario at the heart of the most recent spat.

Lawson, who has previously said the United Kingdom has "nothing to fear" over Brexit, also called pro-Remain Conservative MP Anna Soubry "a fanatic on this issue".

"I fear that he is unhelpful ... he may not intend it but in practice what he is doing is very close to sabotage", Lawson told the BBC. Spending money now on Brexit preparations would divert cash away from priorities such as the NHS and social care and the investment may turn out to be unnecessary if talks result in a good deal, he said.

Lawson has long extolled the virtues of a no deal, saying "too much time and energy is being wasted" on negotiations.

Michel Barnier said the the impasse was "disturbing" and said the European Union was not yet prepared to move onto talk about any future trade deal.